After its most recent redesign to look more like Gmail, Yahoo Mail users are parading a seemingly endless line of problems, including that it doesn't even send email.

The new Yahoo desktop inbox.
(Credit: Yahoo)

Yahoo Mail turned 16 on 8 October, and to celebrate, the company gave the email service a massive overhaul for desktop, iOS and Android. The redesign introduced threaded email conversations, background themes, automatic forwarding and 1TB of storage — and looks suspiciously like the Gmail interface.

And it doesn't work. Users are clamouring in droves all over the internet about the "Yahoo Mail fail", including missing features and strange, glitchy behaviour. By far the biggest complaint over on the Yahoo feedback forum is the removal of tabs, followed by the removal of the "sort by sender" option. Users are also decrying the loss of the toolbar, the removal of the folders sidebar and the formatting of the new inbox.

Yahoo has been performing damage control as much as possible, telling forum users, "The recent design changes in Yahoo Mail are important steps to building a more modern and personalised version. We recognise that this is a lot of change and are actively listening to user feedback so we can continuously make improvements." But the furore has spilled over, with a Change.org petition begging Yahoo to change Mail back, and Twitter and Facebook users taking to the social networks to vent their displeasure.

CNET Australia has reached out to Yahoo for comment and received a prepared statement in reply. "We deeply value how much our users care about Yahoo and are constantly engaging with our products," Yahoo wrote. "We recently made some design changes to Yahoo Mail. These changes are an important step to building a more modern and personalised Yahoo. We recognise that this is a lot of change and are listening to all of the community feedback. Additionally, we're actively measuring user feedback so we can continuously make improvements."

You can go sign the Change.org petition here, and sound off about your experiences with the update in the comments below.